The present invention relates generally to flood control devices for controlling storm-generated runoff water, and specifically to a storm sewer overflow device for controlling storm or flood generated surges of runoff flow into storm sewers.
Conventional municipal flood control systems include storm sewer mains placed parallel to the roads, with individual residential, multi-family or commercial branch lines feeding into the mains. The branch lines and mains are generally horizontally oriented in the ground, and are pitched or inclined a specified amount to facilitate water flow from one location to another. Storm drains are periodically placed along the sides of the roads, and the roads are graded to direct water into these drains. The drains are generally vertically oriented, and are in fluid communication with the mains, and possibly also with branch lines.
During or after heavy rains and/or rapid snow melt, substantial amounts of water are directed into the drains and ultimately into the mains. In some cases, the incoming water volume is greater than the capacity of the mains, and the water, seeking the point of least resistance, may saturate the main line first, not allowing for residential branch lines to drain. This back flow is a major cause of residential flooding. In localities where the sewage sewers and the drain sewers are combined, the backflow may create potentially hazardous health consequences for the flooded residences.
Accordingly, efforts have been made to slow the flow of incoming water to the drains to a rate which can be accommodated by the mains without causing backflow. One such device operates on a vortex principle, when placed in the storm drain. A typical vortex device is made of stainless steel and includes a horizontal portion configured for engaging the main, and a flow control portion configured for receiving the incoming flow and creating a vortex for restricting the amount of water which enters the main through the horizontal portion. In this manner, the vortex device delays the entry of water into the horizontal portion, so that the sewers can accommodate the water without backing up the residential or feed sewer lines.
Conventional vortex devices are provided in various sizes to match main pipe diameters known in the industry. Installation is effected by forcing the horizontal portion into the end of the main which communicates with the storm drain, and employing a hydraulic ram to force a sealing friction fit between the horizontal portion and the inside surface of the main.
This procedure is acceptable in areas where the pipes are relatively new and in good condition. However, in established areas with aged plumbing systems, the pipes become misshapen and/or corroded with age. In areas with clay pipes, the pipes often become oval in shape with age and leaks due to cracking are widespread. The act of forcing the conventional vortex device into fragile, corroded and/or misshapen pipes often causes the pipes to collapse or to be otherwise unacceptable for use. Also, conventional vortex devices are hand fabricated, resulting in significant dimensional deviations. Such deviations in many cases make it difficult to fit vortex devices into pipes.
In situations where the installation of a vortex device causes the pipes to collapse or become otherwise damaged, the area immediately surrounding the installation must be excavated so that a new pipe end may be installed which can accommodate the vortex device. As will be appreciated, this is a time consuming and expensive procedure.
Even when the conventional vortex devices are properly installed and under favorable conditions, the units are heavy due to their stainless steel construction, and difficult to manipulate in the often cramped working conditions of storm drains. Also, conventional vortex devices cannot be removed to clear trapped debris without removing the entire unit. This also requires heavy equipment and often leads to damage or destruction of the pipe in the immediate area.
Thus, there is a need for an improved vortex device which is more easily installed into a variety of operational applications and pipe conditions without damaging or destroying the pipe. There is also a need for such a device which can be removed from the pipe for cleaning or pipe repair without damaging or destroying the pipe.
Accordingly, a first object of the present invention is to provide an improved storm sewer overflow control device which is configured to tightly and securely fit in a variety of pipe diameters and conditions.
Another object of the present invention is to provide an improved storm sewer overflow control device which is installable without the use of heavy equipment.
Still another object of the present invention is to provide an improved storm sewer overflow control device which is easy to remove for the clearing of debris or for pipe repair purposes.
Yet another object of the present invention is to provide an improved storm sewer overflow control device which is lightweight and easily manipulable in storm drains.
A further object of the present invention is to provide an improved storm sewer overflow control device which adequately and/or selectively restricts the incoming flow of flood water to prevent the overloading of sewer mains.
The above-listed objects are met or exceeded by the present storm sewer overflow control device. The purpose of the present unit is to slow the drainage from the street sewer, keeping water on the street longer and giving priority to the residential branch lines until the rain slows down. A first advantage of the present device is that it can be installed in sewer pipes having a variety of dimensions, shapes and conditions. Also, the present device is easy to install or remove from sealing engagement with the pipe using simple hand tools, and in difficult working conditions, namely in the storm drain itself. The use of polymeric materials makes the present device resistant to corrosion, lightweight to handle, inexpensive to produce and affords the capability for mass production, thus resulting in uniform dimensions compared to conventional overflow control devices.
More specifically, a storm sewer overflow control device is provided for controlling runoff surge flows from a first pipe into a generally normally oriented second pipe. The device includes an engagement portion configured for insertion into the second pipe, a flow control portion attachable to the engagement portion and configured for receiving runoff surge flow flowing down the storm drain and slowing the flow for entry into the second pipe through said engagement portion. The engagement portion is radially expandable to engage an interior surface of the second pipe for creating a tight friction fit.
In the preferred embodiment, the engagement portion is configured with at least one component which expands radially as desired to tightly engage the corresponding inner wall of a target pipe. In one embodiment, the expansion is created by axial shortening of the engagement portion. In another embodiment, components of the engagement portion are moved axially to create the radial expansion. In a preferred embodiment, the radial expansion is obtained through the controlled movement of a wedge ring against radially expandable slats. It is also preferred to circumscribe the slats with at least one compressible annular member such as an O-ring or a quad ring. Such an annular member provides a tight frictional relationship against the inside of the pipe. The annular member is compressed against the inside of the pipe by the radially expanding engagement portion, and is prevented from slipping off the fingers by a cone-shaped wedge ring at a distal end of the engagement portion. Once installed, the harder the present device is pulled axially from the sewer mouth, the tighter is the locking action, since the annular member xe2x80x9cwalks upxe2x80x9d the wedge ring, thus increasing its diameter in an opposite direction from the typical tightening direction. Another annular member is preferably provided near the junction of the flow control portion and the horizontal portion, to seal the entry to the pipe and by preventing water from entering the pipe by bypassing the flow control portion. An optional feature is a restrictor disk installable in the device to control the velocity of water flowing into the sewer main.